It was a research flight like no other. In October 2015, a National Science Foundation aircraft was flying over Antarctica to measure the ice thickness as part of NASA's Operation Ice Bridge. On board was a NASA-funded device to monitor in-flight radiation in real time.

Back on the ground, scientists were keeping watch over the readings and noticed something unexpected in the data. Radiation levels spiked and they couldn't figure out why. They were expecting to measure galactic rays, streaming in from space, or radiation from the sun's periodic solar flares, but the radiation spike they saw on this flight, was neither of those things.

Dr. W. Kent Tobiska, the President and Chief Scientist of Space Environment Technologies, describes the 'radiation clouds' as coming from the Earth's own magnetosphere. When solar wind comes in from the sun, it 'jiggles' electrons in the Earth's magnetosphere. Those electrons get funneled down to the atmosphere, which hits oxygen and nitrogen and then sprays gamma rays like a beam towards Earth. When a plane flies through this beam, it's like a 'radiation cloud.'

People who fly through these clouds could be exposed to levels of radiation that exceed monthly allowances.